Environment Canada says "a well organized" snow squall, starting over Lake Huron, will move across the area late this afternoon into the evening hours.
The weather office says it seems very likely the band will impact the afternoon/evening commute in the Golden Horseshoe from Oshawa to Hamilton.
The band is capable of producing quick accumulations of 2 to 5 cm in an hour.
It can also cause sudden reductions in visibility in heavy snow.
The weather agency says the timing of the snowfall could potentially increase afternoon commute times significantly.